[matsadler]

#reachable_objects_from was added in 2.0, and I think #memsize_of was introduced in one of the 1.9 releases. The documentation is new though.

I wrote a little about them here: http://globaldev.co.uk/2013/03/ruby-2-0-0-in-detail/#id6

[conorh]

Ah nice, thanks, missed the part about requiring "objspace" to mix them in and assumed they would be on the already existing ObjectSpace module.